LightSail 2 Successfully Orbits The World Using Only Solar Energy

The Engineer

10 months ago

The Planetary Society has officially carried out a demonstration that was discussed by Carl Sagan on the Tonight Show with Johnny Carson back in 1976. Carl Sagan talked about a new kind of space propulsion known as solar sailing. The final demonstration took ten years of hard work along with seven million dollars in crowdfunding to make LightSail 2 become the very first spacecraft to rely on solar power for raising its orbit.

Bruce Betts, LightSail program
manager and Society’s chief scientist, said, ‘We’re thrilled to announce
mission success for LightSail 2. Our criteria was to demonstrate controlled
solar sailing in a CubeSat by changing the spacecraft’s orbit using only the
light pressure of the Sun, something that’s never been done before.’

The LightSail 2 spacecraft has been
in orbit for more than a month, and last week it opened its sails for the first
time. During the eight days that have passed since then, the spacecraft has
managed to raise its orbit by 1.7 kilometers using only solar power. LightSail
2 follows in the footsteps of IKAROS (from Japan) solar sail becoming the
second successful attempt so far at solar flying. However, unlike IKAROS,
LightSail 2 can use this technique of propulsion for actually changing its
orbit.

As per project manager Dave Spencer,
an onboard algorithm is in charge of autonomously controlling LightSail 2. The
software twists the spacecraft 90 degrees every fifty minutes thus altering the
orientation of the craft. This means that LightSail 2 is able to get energy
from the Sun, regardless of where it is. The amazing algorithm is continuously
being updated and tweaked. The most challenging aspect of the mission so far
has been adjusting the momentum of the spacecraft that is controlled using a
spinning wheel.

Bill Nye, the CEO of The Planetary
Society, said, ‘We are learning a lot from LightSail 2 right now. In other
words, although we’ve declared mission success, and we did this thing that we
have been hoping to do for – depending on how you reckon – 42 years, LightSail
2 will fly for almost another year… We are going to learn a lot about
controlling the spacecraft and the performance of the sails in the next few
months.’

Spencer explained during a press
briefing while talking about the upper limit of altitude, ‘The atmospheric
density at those altitudes is really poorly modeled and highly variable, and so
we don’t really know at what point atmospheric drag is going to overcome our
ability to continue orbit raising. So we’ll keep doing this as long as we can.’

Bill Nye also said, ‘This technology
enables us to take things to extraordinary destinations in the Solar System and
maybe even beyond, in a way that was never possible before, because you don’t
need fuel, you don’t need all the systems to control fuel, manage fuel and buy
fuel.’